If not stabilized, the image streams created by airborne video cameras can be practically unusable for human observation because frame-to-frame image jitter is excessive. This image jitter typically is caused by small, fast pointing errors superposed upon larger-amplitude, slower pointing errors.
It is possible to reduce this image jitter to acceptable levels with refined mechanical stabilization techniques, stabilizing the line of sight of the image so that image jitter amplitude is less than an acceptable limit. Such an approach can deliver high-quality image streams from all types of cameras (video or film) but leads to large, heavy mechanical systems for support of the airborne camera. Such systems are the subject of U.S. Pat. Nos. 5,897,223; 3,638,502; 4,989,466; 4,643,539; and 5,184,521. An approach relying purely upon mechanical stabilization leads to heavy and complex mechanical systems.
Usually, multiple nested mechanical stages of stabilization are required, with each stage reducing the image jitter further, purely by reduction in jitter of the line of sight.
It would be desirable to have a technique to reduce jitter and avoid the need to have such large, heavy, and expensive mechanical systems.